Heart valve defects, such as regurgitation, may be caused by a relaxation of the tissue surrounding the valve. This causes the valve opening to enlarge, which prevents the valve from sealing properly. Such heart conditions are commonly treated by sewing an annuloplasty ring around the valve. Synching the tissue to the ring restores the valve opening to its approximate original size and operating efficiency.
The proper degree of synching, however, is difficult to determine during open heart surgery. This is due to the fact that the patient is under general anesthesia, in a prone position, with the chest wide open, and with a large incision in the heart. These factors affect the normal operation of the valve. Even if the synching is done well, the tissue may continue to relax over the patient's lifetime such that the heart condition returns.
An adjustable annuloplasty ring allows for the proper degree of synching both during open heart surgery and over the patient's lifetime. A subcutaneous adjustment system may be located such that a simple incision will allow access to the adjustment system. The ring prosthesis modification can be done at early onset of recurring regurgitation, with no discomfort to the patient, to stop disease progression with just a simple procedure without a hospital stay, and without a need for an invasive procedure or prolonged anesthesia. The systems and methods disclosed herein are applicable to mitral regurgitation and tricuspid regurgitation using similar construction, design, and numbers of components except for specific routing differences between the mitral valve and the tricuspid valve. The system and methods disclosed herein may also be used for other heart valves.
Certain adjustable annuloplasty rings are described, for example, in U.S. Pat. No. 7,722,668, issued to Moaddeb et al. on May 25, 2010, which is assigned to the assignee of the present disclosure, and which is incorporated by reference herein. Such adjustable annuloplasty rings may include a body member comprising a shape memory material that is responsive to changes in temperature and/or exposure to a magnetic field. Various techniques have been tried for transmitting an activation energy to an annuloplasty ring implanted within a patient's heart to provide the change in temperature and/or exposure to the magnetic field for changing the shape of the body member.